This invention is a device for preventing unauthorized opening of the doors of a cargo container of the type used on truck trailers, storage containers such as those used for ocean-going shipments and construction sites, conex containers such as those used by the military, and the similar type door configurations. Such containers customarily have two doors hinged to laterally opposite sides of the rear of the container on vertical axes and the doors are latched in their closed position by vertical stanchions mounted on the outside of the doors. The stanchions have latching fingers at their tops and bottoms which engage keeper pockets at the top and bottom of the rear of the container when the stanchions are pivoted about their axes. Although various locking devices have been proposed for the handles provided for rotating the stanchions, thieves using bolt cutters, power hack saws and sledgehammers are all too frequently destroying the locking devices.